Safety lock

ABSTRACT

A safety lock suitable for use on dwelling doors comprising a sliding bolt housing adapted to be mounted on a door, a keyreleasable lock assembly adapted to be mounted on the adjacent door frame and an articulated, hardened steel arm having on one end a sliding bolt for coaction with the bolt housing and on the other end a lock plunger for coaction with the lock assembly, thereby permitting the door to be opened only slightly from either side, to permit actuation of the lock assembly from outside or to prevent entry of unwanted persons to the inside.

[ Mar. 11,1975

United States Patent [191 Diaz [ SAFETY LOCK Primary Examiner-Robert L. Wolfe [76] Inventor:

Jose A. Dial, 3901 Kennedy Blvd Attorney, Agent, or Firm.l. Gibson Semmes Union City, NJ. 07087 Oct. 29, 1973 ABSTRACT [22] Filed:

0 m n u o r mm B Na .mw dd Wm o d 0a 2. 8 u.m m 0 h ht l 0 .m m i m ms a m as r AP 5 3 0 l 4 0 N m. D. A .l l 2 on a door, a key-releasable lock assembly adapted to be mounted on the adjacent door frame and an articu- [52] US. 70/93, 292/262 [5]] Int. E05b 65/00 lated, hardened steel arm having on one end a sliding bolt for coaction with the bolt housing and on the 4 3 M4 m D Q M 4 6 2 7/ 32 9 2 7 h c r a e S f 0 d l e .I F .l. 8 5

other end a lock plunger for coaction with the lock assembly, thereby permitting the door to be opened only References Cited UNITED STATES PATENTS slightly from either side, to permit actuation of the lock assembly from outside or to prevent entry of unwanted persons to the inside.

l,773,233 MacKinnon 70/93 3,657,908

Schwartz................................. 70/93 2 Claims, 6 Drawing Figures PATENTED HAR! 1 W5 SHEET 1 or 4 PAIENIEUHARI H975 sum 2 OF 4 FIGBA FIGBB PATENTED 1 I975 3,859,886

SHEU 3 o g SAFETY LOCK FIELD OF THE INVENTION This invention relates to auxiliary door securing devices of the general type commonly known as burglar locks, police locks or chain locks. Such devices have been in use formany years which permit the door to be opened slightly from within or without, but prevent its being opened further until the lock has been released from either the door or the adjacent door frame.

DESCRIPTION OF THE PRIOR ART The prior art discloses numerous examples of door safety locks or mechanical devices to prevent unwanted opening of doors. Kalb and Berger show a door check and lock system in U.S. Pat. No. 768,528 in which the spring biased bolt of a rather conventional door lock is fitted with lateral wings which engage a door-checking arm attached to the frame-mounted keeper for the bolt. The use of a checking arm having a pair of side arms separated by a space for the bolt, which space is accessible from outside the door under the door is partially opened, apparently would provide a good leverage point at which a pry bar could be inserted to defeat the lock. Von Gunten discloses combined door check and lock in U.S. Pat. No. 1,037,377 in which a link is permanently pivoted to the door at one end and slideably engages a frame-mounted keeper at the other end. Although the device may prevent unwanted entry when properly actuated from within, it cannot be actuated from outside when the dwelling occupant leaves. Johanning discloses an articulated padlock and hasp combination which may be opened from either side of the door; however, in use the device may be deactuated only by unlocking the padlock at the door frame and not by simply sliding the hasp member from its keeper on the door, thereby complicating use for the owner.

Hoffman discloses an articulated door locking device in U.S. Pat. No. 1,796,891 in which a keeper arm mounted on the door jam maybe moved into engaging position with a lockable lever member mounted on a sliding bolt affixed to the door; however, the device may not be activated and deactivated from both sides of the door. Ballwanz, et a1 disclose a door fastener suitable for holding a door in the ajar position; however, no provision is made for engaging and disengaging the device from either side of the door. Tannen shows a door fastening device in which a lock actuated, spring biased plunger extends from the door into .engagement with a pivoted keeper attached to the door frame, which restrains the door from more than slight opening; however, the device includes a rather complex arrangement of parts.

SUMMARY OF THE INVENTION This invention relates to a safety lock for use on dwelling or office doors or the like which comprises a restraining arm having first and second ends; a sliding bolt pivotally attached to the first end of the restraining arm and comprising laterally extending projections; means adapted for attachment to a door for releasably retaining the laterally extending projections while permitting lateral movement of the sliding bolt relative to the door; a lock plunger pivotally attached to the second end of the restraining arm and lock means adapted for attachment to a door frame for releasably retaining the lock plunger.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a perspective view of the invention as installed on a door and door frame wherein the door is shown partially opened.

FIG. 2 shows an exploded isometric view of the invention.

FIGS. 3A and 3B show views taken along line 3-3 of FIG. 2, indicating the coaction of the retaining arm and plunger.

FIG. 4 shows a perspective view, partially cut away, of the tumbler locking mechanism used in the invention.

FIG. 5 shows an exploded perspective view of the sliding bolt housing of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT There follows a brief description of the preferred em bodiment of the invention, reference being had to the drawings in which like reference numerals identify like elements of structure in each of the several Figures.

In FIG. 1, the invention is shown assembled to door frame 10 and door 12. Tumbler lock housing 14 engages and secures a lock plunger 16 (FIG. 2) pivotally attached to end 17 of hardened steel door restraining arm 18. Key 20, shown partially in phantom, engages a tumbler lock mechanism 22 (FIG. 4) and is actuable from either side of the door to disengage lock plunger 16. At its opposite end 24 arm 18 is pivotally attached to roller link 26 which in turn is pivotally attached to sliding bolt 28, engaged in sliding bolt housing 30.

In FIG. 2, the components of the invention are shown, partially in phantom, in an exploded perspective view. Tumbler lock housing 14 is a hollow, rectangular box of hardened steel material (See also FIG. 4) which is attached to and extends from mounting plate 92 attached to the door frame 10. Located along the vertical face 31 of the housing most remote from the door opening is an opening 32 for receiving lock plunger guide 34. Located within opening 32 and extending into the interior of housing 14 is lock plunger guide 34 which comprises an essentially U-shaped element of suitably hardened material which extends slightly outside of opening 32 with the open end of the U facing in toward the interior of the building. The guide also includes a slot 36 located in its upper surface and a bias spring 38 and plunger bearing plate 40, which will be described more fully with reference to FIGS. 3A and 3B.

Lock plunger 16 is slideably receivable in plunger guide 34 and includes a sloping cam surface 42, and a slot 44 for displacing and engaging the locking lever 76 of tumbler lock mechanism 22 (See FIGS. 3A, 3B and 4). Arm 18 includes an elongated portion 46 and is formed at ends 17 and 24 into a relatively flat, U- shaped configuration. Plunger 16 is pivotally connected to end 17 via pin 48 as shown; and roller link 26 is pivotally connected to end 24 via pin 50. Roller link 26 includes bored tabs 52 and 54 at either end for connection to adjacent components; and upper and lower recesses 56 and 58, joined by bore 60, for retention of rollers 62 on roller shaft 64. The rollers guide the moving parts to prevent jamming and hangup in motion. Sliding bolt 28 is pivotally connected to roller link 26 via pin 66 and includes on its side facing the door a pair of laterally extending keying projections 68 and 70. The projections 68 and 70 are of essentially rectangular configurations of different sizes and are spaced from bolt 28 by extensions 72 and 74. The keying projections are sized to engage corresponding openings in bolt housing 30, which are discussed with respect to FIG. 5.

FIGS. 3A and 3B show the coaction of the plunger 16, plunger guide 34, bias spring 38, bearing plate 40 and plunger retaining arm 76 of tumbler lock 22. As plunger 16 is forced into guide 34, against the action of spring 38 and plate 40, cam surface 42 will deflect arm 76 upwardly against spring bias. Thereafter, arm 76 will drop through slot 36 in guide 34 and into slot 44 in plunger 16 to secure the plunger against withdrawal until lock 22 is actuated using key 20.

FIG. 4 shows the interior details of tumbler lock housing 14 and its cooperation with the lock mechanism 22. Housing 14 comprises a hollow, rectangular box, as discussed. On vertical face 78 of the box an opening 80 is provided for lock mechanism 22. A partition 82 divides the interior of the housing approximately along its vertical centerline and includes a tapped hole 84 aligned with opening 80. The lock mechanism may thus be screwed into hole 84 and secured in place with set screw 86 so that the lock may not be rotated from outside the housing. Also mounted on partition 82 is plunger retaining arm 76 which is pivoted on adjustment screw 88 and is adjustably biased toward slot 36 in plunger guide 34 by torsion spring 90. Cam surface 91 on lock mechanism 22 moves arm 76 when actuated by key 20. The housing 14 is mounted to mounting plate 92 using suitable fasteners such as screws 94 which are inaccessible when plate 92 is attached to door frame using one-way screws 96. Plate 92 also includes an inwardly extending flange 98 which closely abuts vertical face 78 of the housing 14 to make it difficult to attempt to pry the housing 14 loose from outside the door.

FIG. 5 shows an exploded view of sliding bolt housing 30, its mounting plate 100, sliding bolt retainer 102 and leaf spring 104. As projections 68 and 70 are placed into openings 106 and 108 of housing 30, they and sliding bolt 28 are prevented from moving laterally by retainer 102 which is biased into contact with the inner surface of housing 30 by spring 104, attached to mounting plate 100. Integral with retainer 102 are upwardly and downwardly extending tabs 110 and 112 which extend through slots 114 and 116 of housing 30 when assembled. These tabs may be manually depressed, thereby permitting projection to slide over retainer 102 so that extensions 72 and 74 may enter elongated slot 118 in housing 30.

In operation, the device may be assembled either by first inserting plunger 16 into plunger guide 34 until retainer arm 76 snaps into place in slot 44 and then inserting projections 68 and 70 into openings 106 and 108, depressing tabs and 112 and then sliding bolt 30-along slot 118, as indicated in FIG. I; or, vice versa. While either mode of assembly may be used from the inside of the door, the former mode is simpler when assembling the invention from the outside of the door. Disassembly is achieved at either end using key 20 or sliding bolt 30. If the door is opened when the device has been installed, sliding bolt 28 will move along slot 118 while rollers 62 and 64 move along the upper surface of housing 30, to the position shown in FIG. 1. Rollers 62 and 64 are sized to prevent hang-up of the various elements during movement. At this point, a person within the room may see who is outside but is protected from further opening of the door by the invention. The door may be opened further only by using the key 20 or by closing the door and using sliding bolt 28. The use of hardened steel parts and one way screws minimizes the chances that an intruder will be able to easily break the lock mechanism ofthe invention, while the unique geometry of the invention provides flexibility of assembly and disassembly from both sides of the door.

Having described my invention in such clear and complete detail as to enable one of ordinary skill in the art to make and use it, I claim:

1. A safety lock apparatus comprising:

A. a restraining arm having first and second ends;

B. a sliding bolt pivotally attached in hinged manner to the first end of the restraining arm and comprising laterally extending projections;

C. means adapted for attachment to a door for releasably retaining the laterally extending projections while permitting lateral movement of the sliding bolt relative to the door;

D. a lock plunger pivotally attached in hinged manner to the second end of the restraining arm; and

E. lock means adapted for attachment to a door frame for releasably retaining the lock plunger.

2. The apparatus of claim 1, further including a link pivotally mounted between the sliding bolt and the restraining arm and rollers rotatably mounted to the link for guiding lateral movement of the sliding bolt and re- 

1. A safety lock apparatus comprising: A. a restraining arm having first and second ends; B. a sliding bolt pivotally attached in hinged manner to the first end of the restraining arm and comprising laterally extending projections; C. means adapted for attachment to a door for releasably retaining the laterally extending projections while permitting lateral movement Of the sliding bolt relative to the door; D. a lock plunger pivotally attached in hinged manner to the second end of the restraining arm; and E. lock means adapted for attachment to a door frame for releasably retaining the lock plunger.
 1. A safety lock apparatus comprising: A. a restraining arm having first and second ends; B. a sliding bolt pivotally attached in hinged manner to the first end of the restraining arm and comprising laterally extending projections; C. means adapted for attachment to a door for releasably retaining the laterally extending projections while permitting lateral movement Of the sliding bolt relative to the door; D. a lock plunger pivotally attached in hinged manner to the second end of the restraining arm; and E. lock means adapted for attachment to a door frame for releasably retaining the lock plunger. 